Tapping process of inner thread of stainless steel pipe fitting

- Feb 11, 2019-

Taps are usually used for tapping internal threads on stainless steel pipe fittings.Due to the high viscosity of stainless steel material, poor chip breaking performance, so in the process of tapping, it is easy to appear chip scraping workpiece thread or tap collapse blade phenomenon, affecting the processing efficiency and thread quality.In order to extend the service life of taps and improve the quality of thread processing, the following points should be noted.

(1) choose better tap material.Adding special alloying elements to ordinary high speed tool steel can significantly improve the wear resistance and toughness of the tap.

(2) coating the thread surface of the tap with titanium nitride coating can significantly improve the wear resistance, heat resistance and lubricity of the tap.

(3) appropriately increase the leading Angle of the tap.However, it should be noted that if the leading Angle of the tap is too large, it is easy to cause the blade breakage of the tap and the multi-edge thread of tapping.

In order to solve this problem, some users have to grind the leading part of the tap by themselves. The leading part of the tap before and after grinding is shown in figure 4 and figure 5 respectively.Because of the shape change of the front guide part after grinding, the performance of the tap will still be affected.The way to solve this problem is to maintain the original geometric shape of the front guide part when grinding, it is best to use a tap shovel grinding machine for grinding (or manual grinding on the grinder).The best way to solve the long base surface of the tap is to customize the tap with short base surface according to the specific requirements of the thread to be machined.

 tapping the tap after period of time will become dull, at this time must be timely grinding taps, and after grinding tap often is not working or not durable, the reason is that heavy grinding taps in general is on the floor grinder manual grinding (the thickness of the grinding wheel for 5 ~ 6 mm or thicker) commonly, there is no guarantee that the tap after grinding groove type, rake Angle and slot finish.The groove shape before and after grinding and the chip flow direction during tapping are shown in FIG. 6 and FIG. 7 respectively.

Practice has proved that the best tap Angle for stainless steel pipe fitting is 13.The left and right sides.If the front Angle is too large, it is easy to break the blade after tapping the tap.If the front Angle is too small, then tapping thread finish is poor, and tap tapping resistance is large.In addition, grinding tap easy to form a blade Angle, will also change the chip flow direction.



Cangzhou Steel Pipe Group (CSPG) Co., Ltd. is a large-sized, key metallurgic enterprise of Hebei Province in North China, whose history dates back to 1994. CSPG currently em/paces six member companies with products varying from SSAW, LSAW, ERW, seamless steel pipes to 3PE pipes, galvanized pipes, casing pipes, etc. A Joint-stock corporation, CSPG occupies an area of 600,000 square meters with a total asset of $530 million.

Specialized in the production of straight welded pipe spiral pipe galvanized pipe 3PE/3PP/FBE/TPEP internal and external epoxy powder internal and external epoxy resin cement mortar two cloth three oil buried pipeline IPN8710 non-toxic drinking water internal and external plastic coated lining plastic and other anti-corrosion pipe fittings for oil and gas pipeline water conservancy projects

Executive standard :DIN30670 DIN30678 CSA Z245 AFNOR nf49-710/711 NACE rp0394/0490 AWWAC 210/C213GB/T9711 API 5L ISO 3183Material: Q235B/Q355BGR A GR B x42-x80 l245-l555


Business scope: 21.3mm-3620mmLSAW submerged arc welded pipe 325-2020mmERW straight welded pipe 6mm-711mmSMLS seamless tube 10-1120mmSSAW spiral steel tube 219-3620mmDemand for quality suppliers and partners